Biometric sensor chip having distributed sensor and control circuitry

ABSTRACT

A sensor includes a sensor array formed on a first side of a substrate and at least one circuit operative to communicate with the sensor array formed on a second side of the substrate. At least one via extends through the substrate to electrically connect the sensor array to the at least one circuit. Placing the at least one circuit on the second side of the substrate allows the sensor array to occupy substantially all of the first side of the substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 15/090,474, filed Apr. 4, 2016, entitled “Biometric Sensor ChipHaving Distributed Sensor and Control Circuitry,” which is acontinuation of U.S. patent application Ser. No. 14/294,903, filed Jun.3, 2014, entitled “Biometric Sensor Chip Having Distributed Sensor andControl Circuitry,” which claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Patent Application No. 61/831,586, filed Jun. 5, 2013,entitled “Biometric Sensor Chip Having Distributed Sensor and ControlCircuitry,” the entireties of which are incorporated herein by referenceas if fully disclosed herein.

TECHNICAL FIELD

Embodiments described herein relate generally to a sensor, and moreparticularly to a substrate having a biometric sensor array on a firstside that is coupled to control circuitry positioned on a second side ofthe substrate.

BACKGROUND

Biometric sensing devices are increasingly common in computer or networksecurity applications, financial applications, surveillanceapplications, and system access control applications. Biometric sensingdevices detect or image a unique physical or behavioral trait of aperson, providing biometric data that can reliably identify the person.For example, a fingerprint includes a unique pattern of ridges andvalleys that can be imaged by a fingerprint sensor. The image of thefingerprint, or the unique characteristics of the fingerprint, iscompared to previously captured reference data, such as a referencefingerprint image. The identity of the person is obtained or verifiedwhen the newly captured fingerprint image matches the referencefingerprint image

Devices that image fingerprints or other biometric data can beincorporated into a variety of electronic devices to provide enhancedfunctionality for those devices. Generally, many electronic devices,such as smart phones, tablet computing devices, computers, securitykeypads, and the like, may place a premium on space within the device.That is, the complexity of such devices leads to the incorporation ofadditional components, circuits and the like when compared with previousgenerations of devices. In order to maintain a similar form factorand/or size, the volume and/or area occupied by internal components mayremain constant or even shrink between generations of electronicdevices. Thus, more and more components compete for the same space.Thus, efficient designs of internal components, including biometricsensors, may be both useful and desired.

SUMMARY

Embodiments herein may take the form of a biometric sensor formed on asubstrate (e.g., a “chip”) in such a fashion that electronic componentsare distributed across opposing sides of the substrate. One or morethrough-silicon vias (TSVs) may connect the electronic components on theopposing sides. The TSVs may carry control signals between components,power to one or more components, data between components, and the like.Generally the electronic components may function as if laid out andpositioned on a single side of the substrate.

One embodiment described herein takes the form of a sensor that includesa sensor array formed on a first side of a substrate and at least onecircuit operative to communicate with the sensor array formed on asecond side of the substrate. At least one via extends through thesubstrate to electrically connect the sensor array to the at least onecircuit. Placing the at least one circuit on the second side of thesubstrate allows the sensor array to occupy substantially all of thefirst side of the substrate.

In some embodiments, multiple vias extend through the substrate, andeach via may underlie one of a plurality of traces forming the sensorarray.

In still other embodiments, the multiple vias separate the sensor arrayinto two or more sensor sub-arrays.

In yet other embodiments, each of the two or more sensor sub-arrays isseparately addressable by the at least one circuit.

In some embodiments, an electronic device includes a cover glass and asensor positioned below the cover glass. The sensor includes a sensorarray formed on a first side of a substrate; at least one circuitoperative to communicate with the sensor array formed on a secondopposing side of the substrate; and at least one via extending throughthe substrate to electrically connect the sensor array to the at leastone circuit. The sensor array may occupy substantially all of the firstside of the substrate. As one example, the cover glass and sensor areincluded in a button of the electronic device.

In some embodiments, a method for manufacturing a sensor includesforming one or more vias in a first circuit wafer that includes one ormore electrical components, where each via comprises a blind via thatextends only partially through a thickness of the first circuit wafer. Afirst side of a substrate wafer is formed over a first side of the firstcircuit wafer, where the first side of the first circuit wafer includesopenings to the one or more vias in the first circuit wafer. A temporarycarrier wafer is attached to a second side of the substrate wafer andthe first circuit wafer thinned on a second side of the first circuitwafer to expose the one or more vias in the first circuit wafer. Asecond circuit wafer is then formed over the second side of the firstcircuit wafer, where the second circuit wafer includes a sensor arrayand the one or more vias in the first circuit wafer operably connect theone or more electrical components in the first circuit wafer to thesensor array in the second circuit wafer. An isolator layer can beformed over the second side of the first circuit wafer prior to formingthe second circuit wafer over the second side of the first circuitwafer. Back end of line operations may be performed on the substratewafer prior to attaching the temporary carrier wafer to the second sideof the substrate wafer. In some embodiments, the sensor array includes athree metal redistribution layer of a grounding metal layer and twosensing and drive layers. The temporary carrier wafer is removed fromthe substrate wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a sample device in which an example biometric sensor maybe incorporated;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, showinga relative position of a biometric sensor chip within the sample deviceof FIG. 1;

FIG. 3 is a top plan view of an example biometric sensor;

FIG. 4 is a bottom plan view of the example biometric sensor of FIG. 3;

FIG. 5 is a cross-sectional view of the example biometric sensor ofFIGS. 3-4, taken along line 5-5 of FIG. 3;

FIG. 6 is a top plan view of an example biometric sensor showing asample layout of multiple through-silicon vias;

FIGS. 7A-7I illustrate a process flow diagram depicting one series ofoperations for making a sample biometric sensor; and

FIG. 8 is a flowchart corresponding to the process flow diagram of FIGS.7A-7I.

DETAILED DESCRIPTION

Generally, embodiments herein may take the form of a biometric sensorformed on a substrate (e.g., a “chip”) in such a fashion that electroniccomponents are distributed across opposing sides of the substrate. Oneor more through-silicon vias (TSVs) may connect the electroniccomponents on the opposing sides. The TSVs may carry control signalsbetween components, power to one or more components, data betweencomponents, and the like. Generally, the electronic components mayfunction as if laid out and positioned on a single side of thesubstrate.

In many embodiments, a sensor array may be deposited on a first side ofthe substrate. Likewise, control circuitry (such as CMOS circuits) maybe positioned on a second, opposing side of the substrate. By separatingthe control circuitry and the sensor array in this fashion, the areaavailable on the chip to be occupied by the sensor array may beincreased in comparison to a same-size chip having both sensor andcontrol circuitry on the same side. Thus, embodiments may make moreefficient use of the available area on a chip's surface, and/or mayfacilitate placing a larger sensor on a chip's surface than may beachieved when both the sensor and control circuitry are positioned on asingle side of the substrate.

Further, the control circuitry may be positioned on the second side ofthe substrate in such a fashion that the distance between the controlcircuitry and the sensor may be reduced when compared to biometricsensor packages having both on one side. Essentially, the depth of a TSVconnecting the sensor array to the control circuitry may be less thanthe length of a trace or run that may be required to connect the twowhen the sensor and circuitry occupy a single side of a chip or othersubstrate, as discussed in more detail below. Likewise, the controlcircuitry may be shielded by the substrate from any fringing fieldeffects of the sensor array. FIG. 1 generally depicts a sampleelectronic device that may incorporate a biometric sensor in accordancewith certain embodiments described herein. As can be seen, theelectronic device may take the form of a mobile smart phone. Embodimentsdescribed herein may also be incorporated into, or used with, a varietyof other electronic devices such as tablet computing devices,stand-alone computers, wearable devices, electronics systems forappliances, electronics systems for automobiles, security systems, andthe like.

Although reference is made herein to the orientation of particularobjects and elements, it should be understood that such orientations maybe altered or varied in certain embodiments. Likewise, orientations anddirections discussed herein are generally provided with respect to thefigures herein. Accordingly, “up,” “down,” “upper,” “lower,” “front,”“rear,” “side” and like terms are intended as relative terms, notabsolute.

Referring now to FIG. 1, the biometric sensor may be located beneath anysuitable portion of the exterior of the device 100. The biometric sensormay be located beneath a cover glass 102, for example. Likewise, thebiometric sensor may be located beneath a sidewall 104 or other portionof the device housing. As yet another option, the biometric sensor maybe located beneath an input mechanism 106 of the device 100. One exampleembodiment includes a biometric sensor located beneath a button 108 ofthe device.

In embodiments having a biometric sensor located beneath a cover glassor under a portion of a housing (such as sidewall 104), multiplebiometric sensors may be tiled or otherwise positioned to extend sensingcapability across a larger area of the cover glass/housing.

Similarly, a single biometric sensor may be scaled to underlie asignificant portion of either the cover glass 102 or the housing. Itshould be appreciated that the biometric sensor(s) may be positioned insuch a fashion as to not interfere with viewing of a display through thecover glass 102 (if such a display is present). Thus, for example, thebiometric sensor(s) may be positioned beneath a display element of theelectronic device 100, or sensor may be formed from a relativelyoptically transparent material such as indium-tin-oxide or othersuitable materials.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1, showingan example location of a biometric sensor 200 with respect to the button108 of the sample electronic device 100. Generally, the sensor ispositioned adjacent to the button 108, such that the two touch. Itshould be appreciated that, in alternate embodiments, the sensor 200 andbutton 108 may be at least slightly spaced apart from one another. Aground ring 202 may encircle or be positioned adjacent to the button108. The ground ring may hold a finger or other body portion to bebiometrically sensed at a particular voltage with respect to the sensor200. Although the element is referred to as a “ground ring,” the voltageexerted by the element need not be a zero ground voltage. Likewise, theground ring 202 need not be annular but maybe any suitable shape, whichmay vary with the shape and/or style of the button 108, the sensor 200,or other portion or dimension of the electronic device 100.

An outer surface 204 of the electronic device 100 may abut the groundring 202, or otherwise be positioned near the ground ring 202. Inembodiments where the ground ring 202 is not present, the outer surface204 may be proximate the button 108. The outer surface 204 may define astepped transition or lip that may support the button in someembodiments. Further, in some embodiments, a compliant gel or springelement may be positioned between the lip and the base of the button108, thereby sealing the interior of the electronic device 100 from theexterior and allowing the button 108 to move upwardly and downwardly, asforce is exerted thereon.

In the embodiment shown in FIG. 2, an upper surface of the sensor 200has a sensor array 206 formed thereon; the sensor array 206 may bepositioned proximate to (and in contact with) a lower surface of thebutton 108. By placing the sensor array nearest the button, the distanceat which a finger or other object touching the button is to be scannedor imaged may be minimized. As discussed in more detail below, thesensor array 206 may occupy all or substantially all of the uppersurface of the sensor 200. In this arrangement, the ability of thesensor array 206 to image objects atop or adjacent the top of the button108 may be maximized, since the area occupied by the sensor array on thesensor chip 200 is maximized.

As shown in the cross-sectional view of FIG. 2 and discussed in moredetail below, one or more through-silicon vias (TSVs) 212 may extendthrough the substrate 208 of the sensor 200. The TSVs 212 may generallyelectrically couple the sensor array 206 to certain circuitry 210disposed on an opposing side of the substrate 208. For example, CMOScontrol circuitry 210 may be positioned on a bottom side of thebiometric sensor 200 and connected to the sensor array 206 by the TSVs212. Control and/or data signals may be transmitted between the arrayand the circuitry through the TSVs. The TSVs 212 may be filled with anelectrically conductive material, such as copper or silver, or any othersuitable conductor.

Still with reference to FIG. 2, the sensor 200 may be electricallyconnected to a flex circuit 216 in order to transmit signals to and/orfrom other portions of the electronic device 100. The flex circuit 216may route signals between the sensor 200 and a remote processor, forexample. In order to facilitate electrical communication, one or moreelectrical connection surfaces 214 may be formed on the bottom surfaceof the sensor substrate 208. The exact location of these connectionsurfaces 214 may vary between embodiments. The connection surfaces maytake the form of wire bond pads, bumps or raised surfaces, or any othersuitable connector.

Referring now to FIG. 3, there is shown a top plan view of an examplebiometric sensor 200. The sensor array 206 may be defined by a set ofintersecting rows 300 and columns 302 lines, each of which are formedfrom electrical traces. Generally, either the row lines 300 or thecolumn lines 302 function as drive lines while the other functions assense lines. The intersection of each drive line and sense line maydefine a capacitive sensor element 304 that functions to image abiometric feature of a user's body part that is in contact with, orabove, the button 108. The operation of such a capacitive sensor elementis generally understood and is therefore not described in detail herein.

The capacitive sensor array may be used, for example, as a fingerprintsensor to image the ridges and valleys of a human finger. In alternativeembodiments, the capacitive sensor array may be used as a touch or forcesensor.

As shown in FIG. 3, the ends of each row line and column line 300, 302terminate in a TSV 212. As discussed above, the TSVs 212 mayelectrically connect the row and column lines (and thus the capacitivesensor elements defined by their intersections) with circuitry 210disposed on an opposing side of the substrate 208.

FIG. 4 is a bottom plan view or bottom surface of the example biometricsensor 200 of FIG. 3. In particular, an example disposition of circuitry210 is depicted. As shown in the figure, traces 400 may connect one ormore circuits 210, such as CMOS circuits, to one or more TSVs 212 which,in turn, electrically couple to the sensor array 206 on the top surfaceof the substrate 208. By placing the circuitry 210 on a differentsurface of the substrate 208 than the one occupied by the sensor array206, the array may occupy surface space that would otherwise bededicated to hosting the circuitry. Thus, a larger imaging area may beprovided in a space on a substrate than otherwise achieved if both arrayand circuitry share a common surface.

Additionally, in many embodiments the overall length of an electricalconnection between the sensor array 206 and associated circuitry 210 maybe reduced, insofar as the depth of the TSVs 212 may be less than thelength of a circuit trace that would connect the sensor array andcircuitry if both occupied the same side of the substrate 208. This mayboth simplify the layout, and speed operation, of the sensor 200. Inaddition, the substrate 208 itself may act as a dielectric, shieldingthe circuitry 210 from any fringe field effects of the sensor array (andvice versa). Thus, certain embodiments may essentially provideelectrical shielding to the sensor without introducing any additionallayers or materials, such as a ground plane.

Further, insofar as the connection surfaces 214 are generally closer tothe flex circuit 216 (as shown in FIG. 2), the sensor may be betterintegrated with the flex circuit and the rest of the electronic device100. The connection surfaces 214 need not extend off the sides of thesubstrate 208, for example, and thus potentially may not obstruct anyportion of an adjacent display or the like.

The use of TSVs 212 also obviates the need to wire bond the frontsurface of the biometric sensor 200 to the flex circuit 216, therebypotentially eliminating the need to edge trench the substrate 208 orotherwise provide a path for an external conductive wire from thebiometric sensor's front surface to the flex circuit 216 located beneaththe biometric sensor. This may further free up space inside theelectronic device 100 that would otherwise be used to route theconductor, and may also increase the area available on the substrate 208for use by the biometric sensor array insofar as no edge trench need bedefined.

Referring now to FIG. 5, there is shown a cross-sectional view of theexample biometric sensor 200 of FIGS. 3-4, taken along line 5-5 in FIG.3. As shown to best effect in this figure, the TSVs 212 may be routedbetween the upper sensor array 206 and the lower circuitry 210.Generally, the thickness of the substrate 208 is on the order of 100microns or less, thereby creating a relatively short electrical routingbetween the two surfaces.

FIG. 6 is a top plan view of an example biometric sensor showing asample layout of multiple through-silicon vias (TSVs) 212. The TSVs 212are shown for clarity in this figure, although it should be appreciatedthat in many embodiments, the TSVs 212 may be concealed from externalview by the traces 300, 302 forming the intersecting sets of row andcolumn lines. That is, the diameter of any given TSV 212 may be lessthan the width of an electrical trace 300, 302. As one example, a TSVmay have approximately a 12 micron diameter and a trace may haveapproximately a 25 micron width. Thus, a TSV 212 may connect a row traceor a column trace to associated circuitry 210 (not shown) on theopposing side of the substrate 208, as generally previously described.

By placing the TSVs 212 beneath the traces 300, 302, the sensor array206 may effectively be partitioned into multiple sub-arrays. Forexample, in the embodiment of FIG. 6, the TSVs partition the sensorarray 206 into four separate sensor sub-arrays 600, 602, 604, 606,denoted by the dashed lines in FIG. 6.

Essentially, each sub-array 600, 602, 604, 606 may be addressed by, andtreated as a separate sensor array by the control circuitry 210 or othercircuitry. By partitioning the sensor array 206 in this fashion, it ispossibly to drive and/or read only a portion of the drive and senselines of the array at any given time. This, in turn, may increase theoperating speed of the sensor, insofar as: a) some embodiments maypermit simultaneous operation of multiple sub-arrays 600, 602, 604, 606;and b) the RC constant for any given combination of drive and senselines is lower for a sub-array 600, 602, 604, 606 than for anycorresponding configuration of drive and sense lines of the entire array206. Because the drive and sense lines 300, 302 are reduced in length inthe sub-array configurations, the effective resistance of each trace islowered. Thus, the capacitive sensing elements 304 may discharge morequickly, which provides faster biometric imaging by the biometric sensor200. Resistance may be lowered in this manner because control signalsmay be transmitted through the TSVs 212 at points within the sensorarray, instead of only having control signals carried to the edges ofthe sensor array as in many conventional sensors.

It should be appreciated that the TSVs 212 need not be spaced evenly, asshown in FIG. 6, but may be positioned as desired under the traces ofthe sensor array 206. In some embodiments, the TSVs may be formed insuch a manner that they are symmetric about one or both of an X and Yaxis of the sensor array 206.

In addition, the substrate 208 of the biometric sensor 200 may act as ashield, thereby preventing electrical disturbances from impacting theoperation of the sense and/or drive lines. The separation of the sensorarray 206 and circuitry 210, as accomplished by the use of TSVs 212,enables the substrate 208 to function in this fashion.

An illustrative method of manufacturing the sensor chip will now bediscussed in more detail. FIGS. 7A-7I illustrate a process flow diagramdepicting one series of operations for making a sample biometric sensor.FIG. 8 is a flowchart corresponding to the process flow diagram of FIGS.7A-7I. With reference initially to FIG. 7A, the sensor chipmanufacturing process typically begins with a circuit wafer 700. In manyinstances, the circuit wafer 700 may be silicon. With reference to FIG.8, once a circuit wafer is provided or created, the method 800 may beginwith operation 802 and the circuitry and other components may be addedor otherwise defined in the circuit wafer. For example, front end ofline (FEOL) CMOS processing can be used to add individual devices, e.g.,transistors, capacitors, resistors, and the like, to the circuit wafer.In this example, one or more interconnects, such as metal interconnectlayers, may also be added to the circuit wafer. As shown in FIG. 7B,after operation 802, the circuit wafer includes a plurality ofelectrical components and/or traces 702 defined thereon.

After operation 802, the method 800 may proceed to operation 804. Withreference to FIGS. 7C and 8, in operation 804, one or more vias 704 aredefined within the circuit wafer 700. The via(s) may be defined throughetching, grinding, chemical deposition, or the like. Depending on thethickness of the circuit wafer the one or more vias may be blind viasand may not extend through the entire thickness of the circuit wafer 700during operation 804. For example, the circuit wafer 700 may besufficiently thin that extending the vias 704 through the entirethickness of the circuit wafer could cause the circuit wafer to crack orotherwise hinder additional processing. In these embodiments, the vias704 terminate prior to the opposite edge of the circuit wafer 700.Accordingly, as shown in FIG. 7C, the vias 704 extend onlythree-quarters through the thickness of the circuit wafer 700.

With reference again to FIG. 8, after the vias are defined through thecircuit wafer, the method 800 may proceed to operation 806. In operation806, a substrate wafer is added to the circuit wafer. With reference toFIG. 7D, in operation 806, the substrate wafer 706 is bonded to thecircuit wafer 700 and then back end of line (BEOL) operations may beperformed. For example, contacts (e.g., bond pads), interconnect wires,and/or dielectric structures may be added to the circuit wafer duringoperation 806. Generally, the BEOL processing and substrate wafer willbe added to the side 708 of the circuit wafer 700 that has an openingfor the vias 704. In other words, the face of the circuit wafer 700including the openings to the vias 704 is bonded to the substrate wafer706 and the face 710 without via openings is unbounded.

With reference again to FIG. 8, after operation 806, the method 800 mayproceed to operation 808. In operation 808, a temporary carrier wafer isbonded to the substrate wafer or the other structures formed during BEOLprocessing. With reference to FIG. 7E, the temporary carrier wafer 712may be bonded to the substrate wafer 706. The temporary carrier wafer712 can be bonded to the substrate wafer 706 using a number of differenttechniques, such as, but not limited to, direct bonding, plasmaactivated bonding, eutectic bonding, and/or hybrid bonding.

Once the temporary carrier wafer 712 has been bonded to the substratewafer 706, the method 800 may proceed to operation 810. In operation810, the circuit wafer is thinned to reveal the vias. With reference toFIG. 7F, the circuit wafer 700 is thinned to reduce the thickness suchthat the vias 704 now extend through the entire thickness of the circuitwafer 700. The circuit wafer may be thinned in a number of differentmanners, such as, but not limited to, grinding, polishing, and selectiveetching processes. Because the side 708 of the circuit wafer 700 withthe via openings is bonded to the substrate wafer 706, the grinding orother thinning process is done to the un-bonded or un-processed side710A of the circuit wafer 700 and removes the excess material betweenthe terminal end of the vias, such that the vias 704 can be exposed.

After operation 810, the method 800 may proceed to operation 812. Inoperation 812, an isolator may be applied to the circuit wafer. Withreference to FIG. 7G a dielectric or other isolation layer 714 isapplied to the top of the circuit wafer 700. Once the isolator layer 714is applied, the method 800 may proceed to operation 814. In operation814, one or more metal and/or sensor contacts, such as the sense anddrive lines, are added to or over the isolator layer. With reference toFIG. 7H, one or more layers of metal or other connection elements areadded to a circuit wafer 716. For example, a three metal redistributionlayer (RDL) which may include a grounding metal layer 718 and twosensing/drive layers 720 for the biometric sensor may be added to thecircuit wafer 716 in operation 814.

With reference again to FIG. 8, after the sensor contacts and metalcontacts have been added, the method 800 may proceed to operation 816.In operation 816, the temporary carrier wafer may be removed. Withreference to FIG. 7I, the temporary carrier wafer 712 may be de-bondedor otherwise removed. For example, the temporary carrier wafer may be apolymer material that may be removed using one or more solvents. Asanother example, the temporary carrier wafer may be removed throughgrinding, polishing, or the like.

After the temporary carrier wafer has been removed, the method 800 mayproceed to an end state 818. The example biometric sensor 200 is shownin FIG. 7I.

Although embodiments have been described herein with respect toparticular sensor types, configurations and methods of manufacture, itshould be appreciated that alternative embodiments may vary one or moreof these. For example, certain capacitive sensors, such as touch sensorsand/or force sensors, may employ distribution of sensor arrays andcircuitry across differing surfaces of a substrate as described herein,including connection of the same with TSVs. Likewise, certainembodiments may omit elements described herein, vary the order ofoperations with respect to methods described herein, and the like.

The present disclosure recognizes that personal information data,including biometric data, in the present technology, can be used to thebenefit of users. For example, the use of biometric authentication datacan be used for convenient access to device features without the use ofpasswords. In other examples, user biometric data is collected forproviding users with feedback about their health or fitness levels.Further, other uses for personal information data, including biometricdata, that benefit the user are also contemplated by the presentdisclosure.

The present disclosure further contemplates that the entitiesresponsible for the collection, analysis, disclosure, transfer, storage,or other use of such personal information data will comply withwell-established privacy policies and/or privacy practices. Inparticular, such entities should implement and consistently use privacypolicies and practices that are generally recognized as meeting orexceeding industry or governmental requirements for maintaining personalinformation data private and secure, including the use of dataencryption and security methods that meets or exceeds industry orgovernment standards. For example, personal information from usersshould be collected for legitimate and reasonable uses of the entity andnot shared or sold outside of those legitimate uses. Further, suchcollection should occur only after receiving the informed consent of theusers. Additionally, such entities would take any needed steps forsafeguarding and securing access to such personal information data andensuring that others with access to the personal information data adhereto their privacy policies and procedures. Further, such entities cansubject themselves to evaluation by third parties to certify theiradherence to widely accepted privacy policies and practices.

Despite the foregoing, the present disclosure also contemplatesembodiments in which users selectively block the use of, or access to,personal information data, including biometric data. That is, thepresent disclosure contemplates that hardware and/or software elementscan be provided to prevent or block access to such personal informationdata. For example, in the case of biometric authentication methods, thepresent technology can be configured to allow users to optionally bypassbiometric authentication steps by providing secure information such aspasswords, personal identification numbers (PINS), touch gestures, orother authentication methods, alone or in combination, known to those ofskill in the art. In another example, users can select to remove,disable, or restrict access to certain health-related applicationscollecting users' personal health or fitness data.

We claim:
 1. A biometric sensor, comprising: a capacitive sensor arrayconfigured to image biometric data and formed on a first side of asubstrate, the sensor array comprising: a first plurality of electricaltraces defining a plurality of rows; a second plurality of electricaltraces defining a plurality of columns, the plurality of columnsintersecting the plurality of rows, thereby defining a plurality ofintersections; and a capacitive sensing element formed at each of theplurality of intersections; at least one circuit formed on a secondopposing side of the substrate and configured to communicate with thesensor array; and a plurality of vias extending through the substrate toelectrically connect the sensor array to the at least one circuit;wherein each of the plurality of vias underlies an electrical tracechosen from the first or the second plurality of electrical traces. 2.The biometric sensor of claim 1, wherein the plurality of vias separatesthe sensor array into a plurality of sensor sub-arrays.
 3. The biometricsensor of claim 2, wherein each sensor sub-array in the plurality ofsensor sub-arrays is separately addressable by the at least one circuit.4. The biometric sensor of claim 2, wherein at least one of theplurality of sensor sub-arrays comprises: a subgroup of the plurality ofrows; and a subgroup of the plurality of columns, the subgroup of theplurality of columns intersecting the subgroup of the plurality of rows;wherein an RC constant of the at least one of the plurality of sensorsub-arrays is less than an RC constant of the sensor array.
 5. Thebiometric sensor of claim 2, wherein the plurality of sub-arrays imagesa biometric parameter faster than the sensor array.
 6. The biometricsensor of claim 1, wherein the substrate electrically shields the atleast one circuit from the capacitive sensor array.
 7. A fingerprintsensor, comprising: a sensor array comprising biometric sensing elementsformed on a first side of a substrate, the sensor array comprising: afirst plurality of electrical traces defining a plurality of rows; and asecond plurality of electrical traces defining a plurality of columns,the plurality of columns intersecting the plurality of rows to define aplurality of intersections; wherein a respective biometric sensingelement is formed at each of the plurality of intersections and eachbiometric sensing element is configured to image a fingerprint; at leastone circuit formed on a second opposing side of the substrate andconfigured to communicate with the sensor array; and a plurality of viasextending through the substrate to electrically connect the sensor arrayto the at least one circuit, wherein each of the plurality of vias isformed at a unique end of one of the plurality of rows and the pluralityof columns.
 8. The fingerprint sensor of claim 7, wherein the substrateelectrically shields the at least one circuit from the sensor array. 9.A fingerprint sensor, comprising: a sensor array configured to capturefingerprint data and formed on a first side of a substrate, the sensorarray comprising: a first plurality of electrical traces defining aplurality of rows; and a second plurality of electrical traces defininga plurality of columns, the plurality of columns intersecting theplurality of rows, thereby defining a plurality of intersections; and acapacitive sensing element formed at each of the plurality ofintersections; at least one circuit formed on a second opposing side ofthe substrate and operative to communicate with the sensor array; and aplurality of vias extending through the substrate to electricallyconnect the sensor array to the at least one circuit, wherein each ofthe plurality of vias underlies a trace chosen from the first or secondplurality of traces.
 10. The fingerprint sensor of claim 9, wherein theplurality of vias separates the sensor array into a plurality of sensorsub-arrays.
 11. The fingerprint sensor of claim 10, wherein each sensorsub-array in the plurality of sensor sub-arrays is separatelyaddressable by the at least one circuit.
 12. The fingerprint sensor ofclaim 10, wherein at least one of the plurality of sensor sub-arrayscomprises: a subgroup of the plurality of rows; and a subgroup of theplurality of columns, the subgroup of the plurality of columnsintersecting the subgroup of the plurality of rows; wherein an RCconstant of the at least one of the plurality of sensor sub-arrays isless than an RC constant of the sensor array.
 13. The fingerprint sensorof claim 10, wherein the plurality of sub-arrays images a biometricparameter faster than the sensor array.
 14. The fingerprint sensor ofclaim 9, wherein the substrate electrically shields the at least onecircuit from the sensor array.
 15. An electronic device, comprising: acover layer; and a fingerprint sensor positioned below the cover layer,the fingerprint sensor comprising: a sensor array configured to imagefingerprint data and formed on a first side of a substrate, the sensorarray comprising: a first plurality of electrical traces defining aplurality of rows; a second plurality of electrical traces defining aplurality of columns, the plurality of columns intersecting theplurality of rows to define a plurality of intersections; and acapacitive sensing element formed at each of the plurality ofintersections; at least one circuit formed on a second opposing side ofthe substrate and operative to communicate with the sensor array; and aplurality of vias extending through the substrate to electricallyconnect the sensor array to the at least one circuit; wherein each ofthe plurality of vias underlies an electrical trace chosen from thefirst or the second plurality of electrical traces; or each of theplurality of vias is formed at a unique end of one of the plurality ofrows and the plurality of columns.
 16. The electronic device of claim15, wherein the substrate electrically shields the at least one circuitfrom the sensor array.